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The effect of applied load on density–pressure dependence as well as density distribution under axial pressing of powders in closed dies is analyzed. The continuity hypothesis is used for the analysis. The notion of a representative element is introduced. It is established that the size of this element is related to the effective diameter of powder particles. The sensitivity of density–pressure dependence and density distribution to pressing conditions is explained. Some features of axial pressing with a rotating punch are pointed out. The personal contribution of I. D. Radomyselskii to the formulation and solution of basic problems of powder pressing theory is emphasized.

For dual-pore-fracture rock mass, by considering the effect of facture weakening, a method for determining the cohesion c N and internal friction angle O N of arbitrary plane in a representative element was suggested. It was proven to be reasonable for the coordination of the anisotropy variation curves of rock mass strength obtained by this and Attewell's methods. Introducing the method for the solving of c N and O N into the elastic-plastic FEM code developed by the authors, aimed at a rectangular underground cave, three cases with different fracture states were computed. The results show that with the increasing of fracture set number, the cohesion and internal friction angle of rock mass and the plasticity zone decreased and sharply, nonlinearly grew respectively, and the magnitude and distribution of stress and displacement in the surrounding rock mass changed obviously.

Laboratory metal dusting test of several Ni binary alloys containing the representative element was conducted in a simulated syngas atmosphere at 650°C for 100h. The Ni alloys containing element belonging to Group 14 and 15 in the periodic series exhibited excellent metal dusting resistance, while those containing Group 13 did not. This behavior was able to be reasonably interpreted from the Blyholder mechanism and the concept of Pauling’s electronegativity.

The paper is concerned with the determination of edge effect zone in a laminated composite with laminas subject to longitudinal compression. The dependence of the maximum decay length on the ratio between the period of external loading and the structure parameter is studied. The load period depends on the number of unloaded laminas. The decay of the edge effect is analyzed by numerically solving a boundary-value problem of elasticity for piecewise-homogeneous materials and using a quantitative decay criterion for the near-edge normal stresses

Cold joint in concrete due to delayed concrete placing may cause a reduced shear resistance and increased water permeation. This study presents an analytical model based on the concept of REV (Representative Element Volume) to assess the effect of water permeability in cold joint concrete. Here, OPC (Ordinary Portland Cement) concrete samples with cold joint are prepared and WPT (Water Permeability Test) is performed on the samples cured for 91 days. In order to account for the effect of GGBFS (Granulated Ground Blast Furnace Slag) on water permeability, concrete samples with the same W/B (Water to Binder) ratio and 40% replacement ratio of GGBFS are tested as well. Utilizing the previous models handling porosity and saturation, the analysis technique for equivalent water permeability with effective cold joint width is proposed. Water permeability in cold joint increases to 140.7% in control case but it decreases to 120.7% through GGBFS replacement. Simulation results agree reasonably well with experimental data gathered for sound and cold joint concrete.

The article deals with composite materials with the hybrid spatial reinforced filler. The microstructure studies have been carried out to determine the main properties of the material structure, to choose its representative element and to build up a mathematical composite model. There has been developed the design technique for the stress-strain condition and the procedure of determining the material elastic properties. It has been shown that introduction of an interlayer on the fibre strand boundary results in redistribution of microstresses in the structure, the change of elastic properties and character of composite failure.